| 301 | Texas Petroleum Investment Company | Houston, TX 77057 | Oil & Gas Operator | Dec 2025 |
| 302 | Texoma Production Co | | Oil & Gas Operator | Jun 1986 |
| 303 | The Pioneer | | Gas Operator | Feb 2008 |
| 304 | Thomas Aitken, Inc. | | Gas Operator | Dec 2024 |
| 305 | Time Energy, L.L.C. | | Oil & Gas Operator | Nov 2020 |
| 306 | TMR Exploration, Inc. | Bossier City, LA 71171 | Oil & Gas Operator | Dec 2025 |
| 307 | Tomlinson Oil Co Inc | Great Bend, KS 67530 | Oil & Gas Operator | May 2025 |
| 308 | Tommy Joe Jenny | | Gas Operator | Nov 2024 |
| 309 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 310 | Tracer Energy, Inc. | Graham, TX 76450 | Oil & Gas Operator | Nov 1998 |
| 311 | Trico Oil Co., Inc. | | Gas Operator | Nov 1978 |
| 312 | Tulip Industries, Inc. | | Oil & Gas Operator | Feb 2024 |
| 313 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 314 | Union Diversified, Inc. | | Gas Operator | Dec 2008 |
| 315 | Union Drilling &Management Inc | | Gas Operator | Feb 1991 |
| 316 | United Southern Resources Inc. | | Gas Operator | Nov 2013 |
| 317 | Vanguard Petroleum Corp. | | Gas Operator | Jun 1986 |
| 318 | Velandera Energy Partners LLC | | Oil & Gas Operator | Nov 2024 |
| 319 | Vernon E. Faulconer, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Dec 2024 |
| 320 | Viking Resources | | Oil & Gas Operator | Sep 1995 |
| 321 | Vista Investments | | Gas Operator | Nov 1998 |
| 322 | W M Smith | | Oil Operator | Jun 1989 |
| 323 | W&T Offshore, Inc. | Houston, TX 77057 | Oil & Gas Operator | Dec 2025 |
| 324 | W. B. Inabnet | | Gas Operator | Oct 1985 |
| 325 | W. D. Roberson | | Gas Operator | Mar 2021 |
| 326 | W. J. Wegman, Jr. | | Gas Operator | Dec 1991 |
| 327 | Walker Energy, LLC | | Oil & Gas Operator | Nov 2024 |
| 328 | Watchtower Petroleum, LLC | | Oil & Gas Operator | Jun 2025 |
| 329 | Weiser-Brown Operating Company | Magnolia, AR 71754 | Oil & Gas Operator | Dec 2025 |
| 330 | Wells-Battelstein O&G, Inc. | | Gas Operator | Dec 1986 |
| 331 | White Operating Co., L.L.C. | | Oil & Gas Operator | Oct 2019 |
| 332 | Will-Drill Operating, L.L.C. | Shreveport, LA 71105 | Oil & Gas Operator | Dec 2025 |
| 333 | Will-Drill Production Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Dec 2025 |
| 334 | Windsor Gas Corporation | | Oil & Gas Operator | Aug 1989 |
| 335 | Womack & Nelson | | Gas Operator | Feb 1987 |
| 336 | Woods & Deas | | Oil & Gas Operator | Jan 1984 |
| 337 | Woods Operating Co., Inc. | Shreveport, LA 71136 | Oil & Gas Operator | Dec 2020 |
| 338 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 339 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 340 | Zadeck Energy Group, Inc. | | Oil & Gas Operator | Dec 2011 |